Electronic locking differential with direct locking state detection system

ABSTRACT

An axle assembly with an electronic locking differential that employs a locking mechanism having components that are fixed to one another along an axis such that they co-translate with one another when the actuator that effects the locking and unlocking of the differential is operated.

This application is a continuation of U.S. application Ser. No.12/481,133, filed Jun. 9, 2009, now U.S. Pat. No. 7,744,500, which is acontinuation of U.S. application Ser. No. 11/700,564 filed Jan. 31,2007, now U.S. Pat. No. 7,572,202, the disclosures of which are herebyincorporated by reference as if fully set forth in detail herein.

INTRODUCTION

The present disclosure generally relates to axle assemblies and moreparticularly to an axle assembly having an electronic lockingdifferential.

Commonly owned U.S. Pat. No. 6,958,030 discloses an electromagneticlocking differential assembly that employs an electromagnetic actuatorto selectively couple a side gear to a differential case to cause thedifferential assembly to operate in a fully locked condition. Morespecifically, the electromagnetic actuator is actuated to axiallytranslate an actuating ring (which is non-rotatably coupled to thedifferential case) such that dogs on the actuating ring matingly engagedogs that are formed on a face of the side gear opposite the gear teeth.While such electronic locking differentials are fit for their intendedpurposes, they are nonetheless susceptible to improvement.

SUMMARY

In one form the present teachings provide an assembly that includes adifferential case, a gear set and a locking device. The differentialcase includes a mounting portion and an annular pocket. The gear setincludes first and second side gears and a plurality of pinion gears.The first side gear is proximate a first end of the differential caseand the second side gear is proximate a second end of the differentialcase opposite the first end. The pinion gears meshingly engage the firstand second side gears. The locking device includes a first dog, a seconddog, a return spring, a thrust member, and an actuator. The first dogincludes a plurality of first engaging features and is non-rotatablycoupled to the second side gear. The second dog includes a plurality ofsecond engaging features and is non-rotatably but axially slidablyengaged to the differential case. The return spring biases at least oneof the first and second dogs in a direction so that the first and secondengaging features are not engaged to one another. The thrust memberextends through the differential case. The actuator is mounted about themounting portion and has a plunger. The plunger is movable between afirst position, which permits the return spring to apply a force thattends to decouple the first and second engaging features, and a secondposition in which the thrust member and the second dog are urged axiallytoward the first dog such that the first and second engaging featuresengage one another to thereby inhibit relative rotation between thesecond side gear and the differential case. The plunger, the thrustmember and the second dog are fixedly coupled to one another.

In another form, the present teachings provide an assembly that includesa differential case, a gear set and a locking device. The gear setincludes an output gear. The locking device includes a first dog, asecond dog, a thrust member, and an actuator. The first dog includes aplurality of first engaging features and is non-rotatably coupled to theoutput gear. The second dog includes a plurality of second engagingfeatures and is non-rotatably but axially slidably engaged to thedifferential case. The thrust member extends between the second dog andthe actuator. The actuator has a plunger that is movable between a firstposition, which permits the return spring to apply a force that tends todecouple the first and second engaging features, and a second positionin which the thrust member and the second dog are urged axially towardthe first dog such that the first and second engaging features engageone another to thereby inhibit relative rotation between the second sidegear and the differential case. The plunger, the thrust member and thesecond dog are fixedly coupled to one another.

Further areas of applicability will become apparent from the descriptionprovided herein. It should be understood that the description andspecific examples are intended for purposes of illustration only and arenot intended to limit the scope of the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings described herein are for illustration purposes only and arenot intended to limit the scope of the present disclosure in any way.

FIG. 1 is a schematic illustration of a vehicle having a drivelineconstructed in accordance with the teachings of the present disclosure;

FIG. 2 is a partially broken away perspective view of a portion of thevehicle of FIG. 1, illustrating the rear axle assembly in more detail;

FIG. 3 is an exploded perspective view of a portion of the rear axleassembly, illustrating the differential assembly in more detail;

FIG. 4 is a partially broken away perspective view of the differentialassembly;

FIG. 5 is an exploded perspective view of a portion of the rear axleassembly, illustrating the differential assembly in more detail;

FIG. 6 is a perspective view of a portion of the rear axle assembly,illustrating a portion of the locking mechanism in more detail; and

FIG. 7 is a perspective view of a portion of the rear axle assembly,illustrating a portion of the locking mechanism in more detail.

DETAILED DESCRIPTION OF THE VARIOUS EMBODIMENTS

With reference to FIG. 1 of the drawings, an exemplary vehicle 10 isschematically shown and can include a power train 12 and a drive train14. The power train 12 can include a power source, such as an internalcombustion engine 16 and a transmission 18 that can receive rotary powerfrom the engine 16 and output power to the drive train 14. The drivetrain 14 can include a transfer case 20, a rear propeller shaft 22, arear axle assembly 24, a front propeller shaft 26 and a front axleassembly 28. The transfer case 20 can be employed to transmit drivetorque from the transmission 18 to the rear and front axle assemblies 24and 28. The transfer case 20 can include an input shaft (notspecifically shown), which can be coupled to the transmission 18 toreceive rotary power therefrom, a rear output shaft 30, which can becoupled to the rear propeller shaft 22, and a front output shaft 32 thatcan be coupled to the front propeller shaft 26. The rear propeller shaft22 can transmit rotary power from the rear output shaft 30 to an inputpinion 34 of the rear axle assembly 24. The front propeller shaft 26 cantransmit rotary power from the front output shaft 32 to an input pinion36 of the front axle assembly 28. The rear axle assembly 24 can includea differential assembly 38 that can be driven by the input pinion 34 andcan output rotary power to drive a pair of rear vehicle wheels 40.Similarly, the front axle assembly 28 can include a differentialassembly 42 that can be driven by the input pinion 36 and can outputrotary power to drive a pair of front vehicle wheels 42.

The front and rear axle assemblies 24 and 28 can be similar in theirconstruction and operation and as such, only the rear axle assembly 24will be discussed in detail herein. With additional reference to FIG. 2,the rear axle assembly 24 can include an axle housing 50, a differentialassembly 38 and a pair of axle shafts 54 (only one of which isspecifically shown). The axle housing 50 can be conventionallyconfigured and can include a housing structure 60 and a pair of bearingcaps 62 that can be fixedly but removably coupled to the housingstructure 60. The housing structure 60 can define a differential cavity64 that houses the differential assembly 38. The bearing caps 62 can bedecoupled from the housing structure 60 to permit the differentialassembly 38 to be received within the differential cavity 64. The axleshafts 54 can be coupled to opposite sides of the differential assembly38 and to respective ones of the rear vehicle wheels 40 (FIG. 1) in anyappropriate manner.

With additional reference to FIGS. 3 and 4, the differential assembly 38can include a differential case 70, a ring gear 72 (FIG. 2), a gear set74, a locking system 76 and the input pinion 34 (FIG. 2). The inputpinion 34 and the ring gear 72 can be conventionally constructed andmounted in the axle housing 50 and as such, need not be discussed insignificant detail herein. Briefly, the input pinion 34 can be coupledto the axle housing 50 via a set of bearings (not specifically shown)and disposed about a rotational axis that is generally perpendicular toa rotational axis of the differential case 70. The input pinion 34 caninclude a plurality of pinion teeth (not shown) that can be meshinglyengaged to a plurality of ring gear teeth (not specifically shown)formed on the ring gear 72.

The differential case 70 can include a body portion 80 and acircumferentially-extending flange 82 that is coupled to (e.g.,integrally formed with) the body portion 80. The flange 82 can include aplurality of apertures 84 that can facilitate the removable coupling ofthe ring gear 72 via a plurality of threaded fasteners 86.

The body portion 80 can define a gear set cavity 90 and one or moreassembly windows 92, which can be employed to install the gear set 74into the gear set cavity 90. In the example provided, the body portion80 includes first and second side segments 100 and 102, respectively,and first and second end segments 104 and 106, respectively. Each of thefirst and second side segments 100 and 102 can include a through-bore108, which can be arranged generally perpendicular to the rotationalaxis of the differential case 70, and a boss 110 that can be disposedconcentrically about the through-bore 108 within the gear set cavity 90.A relatively large fillet radius 112 can be employed at the intersectionbetween the second end segments and the first and second side segments100 and 102.

Each of the first and second end segments 104 and 106 can span betweenthe first and second side segments 100 and 102 and can include a hollow,axially extending trunnion 120. Each trunnion 120 can define an insidediameter, which can be sized to receive a corresponding one of the axleshafts 54 there through, and an outside diameter that can be sized toengage a bearing 124 (FIG. 2) that is disposed between the housingstructure 60 and the bearing cap 362. Those of ordinary skill in the artwill appreciate that the differential case 70 may be mounted to the axlehousing 50 via the bearings 124 for rotation within the differentialcavity 64 about the aforementioned rotational axis.

A retaining bore 128 can be formed through the first end segment 104 anda portion of the second side segment 102 and can intersect thethrough-bore 108. A first annular pocket 130 can be formed in theinterior face of the first end segment 104 and can be concentric withthe trunnion 120. The first annular pocket 130 can include a first boreportion 132 and a second bore portion 134 that can be concentric withand relatively smaller in diameter than the first bore portion 132.

The second end segment 106 can include an outer portion that defines amounting hub 140 and an interior portion that defines a second annularpocket 142. The mounting hub 140 can be disposed between the flange 82and the trunnion 120 and can include an actuator mount surface 150 thatcan be generally concentric with the trunnion 120. A circumferentiallyextending groove 152 can be formed in the actuator mount surface 150. Aplurality of actuator apertures 154 can be formed axially through thesecond end segment 106 and can intersect the second annular pocket 142.The second annular pocket 142 can include a pocket portion 160, aplurality of locking features 162 and a thrust ring pocket 164. In theexample provided, the pocket portion 160 is generally circular in shapeand the locking features 162 can be recesses that can intersect thepocket portion 160. The locking features 162 can be shaped in anyappropriate manner and in the example provided, have a half-circle shapethat extends from the pocket portion 160. The thrust ring pocket 164 canbe circular in shape and concentric with the pocket portion 160.

The gear set 74 can include first and second side gears 170 and 172,respectively, first and second pinion gears 174 and 176, respectively, across-shaft 178 and a retaining bolt 180. The first side gear 170 caninclude an annular gear portion 190, which can have a plurality of gearteeth, an annular hub portion 192, which can intersect the gear portion190 at a flange face 194, and a splined aperture 196 that can engage amating splined segment (not shown) formed on a corresponding one of theaxle shafts 54. The hub portion 192 can be sized to be received in thesecond bore portion 134 in the first end segment 104, while a portion ofthe gear portion 190 can be received in the first bore portion 132. Inthe particular example provided, a thrust washer 200 is disposed overthe hub portion 192 and abuts the flange face 194.

The second side gear 172 can include a gear portion 210, which can havea plurality of gear teeth, a tubular hub portion 212 and a splinedaperture 216. The tubular hub portion 212 can axially extend from thesecond side gear 172 in a direction opposite the gear portion 210. Thesplined aperture 216 can be formed through the tubular hub portion 212and can engage a mating splined segment (not shown) formed on acorresponding one of the axle shafts 54. The second side gear 172 can bereceived in the first pocket portion 160 of the second end segment 106.A thrust washer 220 can be disposed in the thrust ring pocket 164between the interior surface 222 of the second end segment 106 and anaxial end face 224 of the tubular hub portion 212. It will beappreciated that the thickness of the thrust washer 220 can be selectedto control the lash between the teeth of the second side gear 172 andthe teeth of the first and second pinion gears 174 and 176.

The first and second pinion gears 174 and 176 can be rotatably mountedon the cross-shaft 178 and meshingly engaged to the teeth of the firstand second side gears 170 and 172. The cross-shaft 178 can extendthrough the through-bores 108 in the first and second side segments 100and 102. Washer-like spacers 230 can be employed to control the lashbetween the first and second pinion gears 174 and 176 and the first andsecond side gears 170 and 172. The retaining bolt 180 can be insertedinto the retaining bore 128 and threadably engaged to a mating threadedaperture 232 formed in the cross-shaft 178 to thereby fixedly securecross-shaft 178 to the differential case 70.

The locking system 76 can include a first dog ring 240, a second dogring 242, a return spring 244, a spacer ring 246, a thrust plate 248, anactuator assembly 250, a first retaining ring 252 and a second retainingring 260.

With reference to FIGS. 3 through 5, the first dog ring 240 can becoupled (e.g., integrally formed) with the second side gear 172 on aportion thereof opposite the gear portion 210. The first dog ring 240can include a plurality of circumferentially spaced apart radiallyextending teeth 270 and a circular groove 272 that can be disposedbetween the tubular hub portion 212 and the teeth 270. In the exampleprovided, the teeth 270 are relatively numerous and shallow so as toprovide increased strength and load sharing between the teeth 270 aswell as to lower tooth contact stresses.

The second dog ring 242 can include an annular body portion 280, aplurality of mating locking features 282, a circular groove 284 and apilot portion 286. The annular body portion 280 can be received in thepocket portion 160 of the second annular pocket 142 and can include aplurality of teeth 290 that are configured to matingly engage the teeth270 of the first dog ring 240. The circular groove 284 can be disposedradially inwardly of the teeth 290 and can generally correspond to thecircular groove 272 formed in the first dog ring 240. The pilot portion286 can be an annular axially projecting rim that can aid in retainingthe return spring 244 to the second dog ring 242. Additionally oralternatively, the pilot portion 286 can engage a mating feature formedon the first dog ring 240 or the second side gear 172 that can guide oraid in guiding the teeth 290 of the second dog ring 242 into engagementwith the teeth 270 of the first dog ring 240. The mating lockingfeatures 282 can be coupled to the annular body portion 280 and in theexample provided, comprise tabs that are semi-circular in shape. Themating locking features 282 are configured to engage the lockingfeatures 162 in the second annular pocket 142 to permit the second dogring 242 to be non-rotatably coupled to the differential case 70 butaxially movable relative to the differential case 70 along therotational axis of the differential case 70.

The spacer ring 246 can be unitarily formed from a suitable material,such as a polymer, which can be non-magnetic. The spacer ring 246 caninclude a spacer body 300 and means 302 for coupling the spacer body 300to the second dog ring 242 and the thrust plate 248. The spacer body 300can include a generally flat body portion 304 and a plurality of legsleeves 306 that can be disposed about the body portion 304. The legsleeves 306 can be shaped as a portion of a hollow cylinder and candefine a retainer aperture 308. The coupling means 302 can be anyappropriate means for fixedly or fixedly but removably coupling thespacer body 300 to the second dog ring 242. For example, the couplingmeans 302 can comprise adhesives, welds, rivets, threaded fasteners,pins, keys, etc. In the particular example provided, the coupling means302 includes a plurality of fastening members 310 that extend from thebody portion 304. Each fastening member 310 can include a leg portion312, which can extend radially inwardly from the body portion 304, andan arm portion 314 that can be generally perpendicular to the legportion 312. The arm portion 314 can include a barb structure 316 thatcan be configured to engage the second dog ring 242. In the particularexample provided, the barb structure 316 includes a pair of taperedleading edges 318, a pair of abutting walls 320 and a central slit 322.When the body portion 304 of the spacer ring 246 is abutted against thesecond dog ring 242, the tapered leading edges 318 of the barbstructures 316 contact the surface of locking apertures 326 that areformed in the second dog ring 242, causing the barb structures 316 todeflect inwardly. It will be appreciated that the locking apertures 326can be chamfered to facilitate the deflection of the barb structures 316as the barb structures 316 are being inserted to the locking apertures326. When the barb structures 316 have passed through the second dogring 242, the barb structures 316 can return to their normal shape tomaintain the abutting walls 320 and the body portion 304 locked againstopposite sides of the second dog ring 242 in a snap-fit manner asillustrated in FIG. 6. In the particular example shown, the abuttingwalls 320 of the barb structures 316 are tapered so as to draw thespacer ring 246 into abutment with the second dog ring 242 when the twoare coupled together. Construction in this manner permits the twocomponents to be abutted against one another despite dimensionalvariation in the fabrication of the second dog ring 242 and the spacerring 246 to thereby minimize or eliminate end play between the twocomponents. The spacer ring 246 can be disposed within the pocketportion 160 about the locking features 162 and can be positioned axiallybetween the second dog ring 242 and the surface 160 a of the pocketportion 160.

The return spring 244 can be any appropriate spring and can bias thefirst and second dog rings 240 and 242 apart from one another. In theexample provided, the return spring 244 is a double wave spring that canbe disposed in the circular grooves 272 and 284. It will be appreciatedthat the return spring 244 can bias the second dog ring 242 intoabutment with the spacer ring 246 and the spacer ring 246 into abutmentwith the second end segment 106.

The thrust plate 248 can be unitarily formed of an appropriate material,such as a polymer. The thrust plate 248 can include a plate portion 350,a plurality of leg members 352, a means 354 for coupling the leg members352 to either the second dog ring 242 or the spacer ring 246, and ameans 356 for coupling the thrust plate 248 to the actuator 250. Theplate portion 350 can have an annular shape and can be sized so as to beslidably received over the actuator mount surface 150. The leg members352 can be coupled to the plate portion 350 and can extend axiallythrough the actuator apertures 154 formed in the second end segment 106.The end of the leg members 352 opposite the plate portion 350 can engagethe second dog ring 242 in an appropriate area. In the example provided,the thrust plate 248 include four leg members 352 each of which abuttinga corresponding one of the mating locking features 282. The couplingmeans 354 can include any suitable means for fixedly or fixedly butremovably coupling the thrust plate 248 to the spacer ring 246 or thesecond dog ring 242, including pins, rivets, threaded fasteners,adhesives, etc. In the particular example provided, the coupling means354 includes locking tabs 358 that can be formed on the leg members 352and configured to engage the retainer apertures 308 that are formed inthe leg sleeves 306. In this example, the leg sleeves 306 extend throughthe actuator apertures 154 and abut the plate portion 350 when thelocking tabs 358 are received in the retainer apertures 308 to therebylock the second dog ring 242, the spacer ring 246 and the thrust plate248 to one another as illustrated in FIG. 7.

The actuator assembly 250 can be generally similar to that which isdescribed in copending U.S. patent application Ser. No. 11/507,311 filedAug. 21, 2006 entitled “Electronically Actuated Apparatus Using SolenoidActuator With Integrated Sensor”, the disclosure of which is herebyincorporated by reference as if fully set forth in detail herein.Briefly, the actuator assembly 250 can be a linear actuator having aplunger 380, a solenoid 382 that can be selectively activated to movethe plunger 380, one or more sensors 384 that can be employed to sense aposition of the plunger 380 and responsively generate a sensor positionsignal, a bushing 390 and an anti-rotate bracket 392.

The bushing 390 can be formed of an appropriate material, such as anoil-impregnated sintered bronze conforming to ASTM B438. The bushing 390can have an outer diameter, which can be sized to engage the solenoid382 via an interference fit. The bushing 390 can define an innerdiameter that is sized to be journally supported on the actuator mountsurface 150 (FIG. 4) of the mounting hub 140 (FIG. 4) of thedifferential case 70 (FIG. 4). The anti-rotate bracket 392 can be formedof an appropriate material, such as a material having a low magneticsusceptibility (e.g., 316 stainless steel), and can be coupled to thesolenoid 382 by an appropriate coupling means, such as fasteners (e.g.,threaded fasteners, rivets), welds or adhesives. The anti-rotate bracket392 can be configured to engage the opposite lateral surfaces of anassociated one of the bearing caps 62 (FIG. 2) so as to inhibit relativerotation between the axle housing 50 (FIG. 2) and the actuator assembly250.

Returning to FIGS. 3 through 5, the plunger 380 can be slidably receivedonto the mounting hub 140 and coupled to the thrust plate 248 via thecoupling means 356. The coupling means 356 can comprise any appropriatefor fixedly or fixedly but removably coupling the plunger 380 to thethrust plate 248. In the particular example provided, the coupling means356 includes a hub portion 400, which extends from the plate portion 350on a side opposite the leg members 352, and a retaining ring groove 402that extends circumferentially about the hub portion 400. The hubportion 400 can be sized to be received into a central bore 404 that isformed in the plunger 380. The retaining ring groove 402 can bepositioned on a side of the plunger 380 opposite its front face 406 andthe first retaining ring 252 can be received in the retaining ringgroove 402 to thereby couple the plunger 380 to the thrust plate 248. Itwill be appreciated that the plunger 380 is effectively coupled to thesecond dog ring 242 in the example provided such that movement of one ofthe plunger 380 and the second dog ring 242 will cause correspondingmovement of the other one of the plunger 380 and the second dog ring242.

The solenoid 382 can be slidably received onto the mounting hub 140 andabutted against the plunger 380. The second retaining ring 260 can bereceived in the circumferentially extending groove 152 in the actuatormount surface 150 and can inhibit axial withdrawal of the actuatorassembly 250 from the mounting hub 140.

When the actuator assembly 250 is actuated, the plunger 380 willtranslate the thrust plate 248 such that the leg members 352 urge thesecond dog ring 242 toward the first dog ring 240 such that the teeth270 and 290 of the first and second dog rings 240 and 242 engage oneanother. As the second dog ring 242 is non-rotatably coupled to thedifferential case 70 and as the first dog ring 240 is non-rotatablycoupled to the second side gear 172, engagement of the teeth 270 and 290inhibits rotation of the second side gear 172 relative to thedifferential case 70, thereby locking the differential assembly 38 (FIG.2) to inhibit speed differentiation between the axle shafts 54 (FIG. 2).It will be appreciated that the anti-rotate bracket 392 can contact thesides of the adjacent bearing cap 62 (FIG. 2) to thereby inhibit orlimit rotation of the actuator assembly 250 relative to the axle housing50 (FIG. 2). It will be appreciated that as the actuator 250 is immersedin a fluid (i.e., a lubricating and cooling oil), apertures 444 in theplunger 380 can be sized and shaped to reduce surface tension andfriction.

With specific reference to FIG. 5, the plunger 380 can include a pair oftab members 450 a and 450 b. A sensor target 452, which can be formed ofa ferro-magnetic material, can be overmolded onto the tab member 450 a.The tab member 450 b can be received in a corresponding slot (not shown)in the solenoid 382; the slot and the tab member 450 b can cooperate toinhibit relative rotation between the plunger 380 and the solenoid 382.

In the example provided, the sensor 384 includes a pair of digitalHall-effect sensors. A first one of the digital Hall-effect sensors canbe programmed to output a first signal when the plunger 380 (andtherefore the second dog ring 242) is in a position furthest from thefirst dog ring 240, and a second signal when the plunger 380 (andtherefore the second dog ring 242) is in a position closest to the firstdog ring 240. Similarly, the second one of the digital Hall-effectsensors can be programmed to output a third signal when the plunger 380(and therefore the second dog ring 242) is in a position furthest fromthe first dog ring 240, and a fourth signal when the plunger 380 (andtherefore the second dog ring 242) is in a position closest to the firstdog ring 240. The first and fourth signals can have a first voltage andthe second and third signals can have a second, different voltage.Construction in this manner provides a level of redundancy that providesfor a robust design and the capability to more readily identify faultsin the operation of the sensor 384.

While specific examples have been described in the specification andillustrated in the drawings, it will be understood by those of ordinaryskill in the art that various changes may be made and equivalents may besubstituted for elements thereof without departing from the scope of thepresent disclosure as defined in the claims. Furthermore, the mixing andmatching of features, elements and/or functions between various examplesis expressly contemplated herein so that one of ordinary skill in theart would appreciate from this disclosure that features, elements and/orfunctions of one example may be incorporated into another example asappropriate, unless described otherwise, above. Moreover, manymodifications may be made to adapt a particular situation or material tothe teachings of the present disclosure without departing from theessential scope thereof. Therefore, it is intended that the presentdisclosure not be limited to the particular examples illustrated by thedrawings and described in the specification as the best mode presentlycontemplated for carrying out this invention, but that the scope of thepresent disclosure will include any embodiments falling within theforegoing description and the appended claims.

1. An assembly comprising a differential case, a gear set and a lockingdevice, the gear set including first and second side gears and aplurality of pinion gears, the pinion gears meshingly engaging the firstand second side gears, the locking device including a first dog, asecond dog, a return spring, a thrust member, and an actuator, the firstdog including a plurality of first engaging features and beingnon-rotatably coupled to the second side gear, the second dog includinga plurality of second engaging features and being non-rotatably butaxially slidably engaged to the differential case, the return springbiasing the second dog away from the first dog, the thrust memberextending through the differential case, the actuator being mountedabout the differential case and comprising a plunger that is movablebetween a first position in which the first engaging features aredecoupled from the second engaging features, and a second position inwhich the first engaging features are engaged with the second engagingfeatures to thereby inhibit relative rotation between the second sidegear and the differential case; wherein the plunger, the thrust memberand the second dog are fixedly coupled to one another in an axialdirection.
 2. The assembly of claim 1, wherein the second side gear andthe first dog are integrally formed.
 3. The assembly of claim 1, whereinthe return spring is disposed between the first and second dogs.
 4. Theassembly of claim 3, wherein one of the first and second dogs includes apilot portion onto which the return spring is received.
 5. The assemblyof claim 1, wherein the thrust member comprises an annular plate that isreceived on a mounting portion of the differential case.
 6. The assemblyof claim 1, wherein the actuator comprises a bracket that is adapted toengage a housing to limit rotation of the actuator relative to thehousing.
 7. The assembly of claim 1, wherein the actuator includes asensor that is configured to sense a position of at least one of theplunger, the second dog and the thrust member and responsively generateat least one sensor signal.
 8. The assembly of claim 1, wherein thesecond dog includes a body portion and a plurality of locking featuresthat extend from the body portion.
 9. The assembly of claim 8, whereinthe thrust member comprises a plurality of leg members, each of the legmembers extending through an associated actuator aperture formed in thedifferential case, each of the leg members engaging an associated one ofthe locking features.
 10. The assembly of claim 9, wherein the lockingdevice further comprises a spacer, the spacer being coupled to at leastone of the thrust member and the second dog.
 11. The assembly of claim10, wherein the spacer includes a plurality of barb structures forengaging one of the second dog and the thrust member.
 12. The assemblyof claim 11, wherein the one of the second dog and the thrust memberincludes a plurality of locking apertures for receiving the barbstructures.
 13. The assembly of claim 10, wherein one of the spacer andthe thrust member includes a tab and the other one of the spacer and thethrust member includes a retainer aperture that is configured to receivethe tab.
 14. The assembly of claim 13, wherein the tabs are formed onthe leg members.
 15. The assembly of claim 14, wherein the spacerincludes a leg sleeve that at least partially conforms to one of the legmembers and wherein the retainer aperture is formed in the leg sleeve.16. The assembly of claim 1, wherein one of the thrust member and theplunger includes a hub portion having a circumferential groove formedthereon, and the other one of the thrust member and the plunger includesan bore into which the hub portion is received, and wherein the lockingdevice includes a retaining member that is received in thecircumferential groove to inhibit removal of the hub portion from thebore.
 17. The assembly of claim 1, wherein the first and second engagingfeatures comprise teeth.
 18. The assembly of claim 1, wherein theactuator includes a solenoid that is axially fixed to the differentialcase, and wherein the plunger is axially moveable relative to thesolenoid and the differential case.
 19. The assembly of claim 13,wherein one of the spacer and the thrust member includes a tab and theother one of the spacer and the thrust member includes a retaineraperture that is configured to receive the tab.
 20. An assemblycomprising a differential case, a gear set and a locking device, thegear set including first and second side gears and a plurality of piniongears, the pinion gears meshingly engaging the first and second sidegears, the locking device including a first dog, a second dog, a thrustmember, and an actuator, the first dog including a plurality of firstengaging features and being non- rotatably coupled to the second sidegear, the second dog including a plurality of second engaging featuresand being non-rotatably but axially slidably engaged to the differentialcase, the thrust member extending through the differential case, theactuator being mounted about the differential case and comprising aplunger that is movable between a first position in which the firstengaging features are decoupled from the second engaging features, and asecond position in which the first engaging features are engaged withthe second engaging features to thereby inhibit relative rotationbetween the second side gear and the differential case; wherein theplunger, the thrust member and the second dog are fixedly coupled to oneanother in an axial direction.
 21. An assembly comprising a differentialcase, a gear set and a locking device, the gear set including first andsecond side gears and a plurality of pinion gears, the pinion gearsmeshingly engaging the first and second side gears, the locking deviceincluding a first dog, a second dog, a return spring, a spacer, a thrustmember, and an actuator, the first dog including a plurality of firstengaging features and being non-rotatably coupled to the second sidegear, the second dog including a plurality of second engaging featuresand being non-rotatably but axially slidably engaged to the differentialcase, the return spring being disposed between the first and second dogsand biasing the second dog away from the first dog, the thrust memberextending through the differential case, the spacer being disposedbetween the thrust member and the second dog, the actuator being mountedabout the differential case and comprising a plunger that is movablebetween a first position in which the first engaging features aredecoupled from the second engaging features, and a second position inwhich the first engaging features are engaged with the second engagingfeatures to thereby inhibit relative rotation between the second sidegear and the differential case; wherein the plunger, the thrust member,the spacer and the second dog are fixedly coupled to one another in anaxial direction.
 22. The assembly of claim 4, wherein the second dogincludes a body portion and a plurality of locking features that extendfrom the body portion, wherein the thrust member includes a plurality ofleg members, each extending through an associated actuator apertureformed in the differential case, and wherein each of the leg membersengages an associated one of the locking features.
 23. The assembly ofclaim 22, wherein the spacer includes a plurality of barb structures forengaging one of the second dog and the thrust member, and wherein theone of the second dog and the thrust member includes a plurality oflocking apertures for receiving the barb structures.
 24. The assembly ofclaim 23, wherein the tabs are formed on the leg members, and whereinthe spacer includes a leg sleeve that at least partially conforms to oneof the leg members, and wherein the retainer aperture is formed in theleg sleeve.